If the next mayor wants to get serious about having a city workforce that reflects the city, he or she is going to have to tackle what is called the Rule of Two.

If that sounds obscure, it is because it is.

The Rule of Two was inserted into the City Charter when it was written in the early 1950s. It's an essential part of the city's civil service system and it states, to oversimplify, that all applicants for jobs and promotions must take a civil service examination and that the position must be filled from a list of the top two scorers.

There was a good reason to insist on a merit-based civil service system when the new charter was being written. In those days, the machine (in this case, the Republican Party organization) had a hammerlock on hiring and promotion.

Most jobs - and that includes police and firefighters, clerks and enforcement officers - only went to those with political sponsors.

That old patronage system is gone, for the most part. Today, 92 percent of all city government jobs are civil service.

The flip side of that equation - very evident 64 years after passage of the new charter - is that the local government workforce doesn't reflect the city of today. Blacks, Latinos, and Asians are underrepresented when it comes to local government jobs. Women of all races and ethnic origins are as well.

This is an example of where the facts don't jibe with people's perceptions. After all, we have an African American mayor, and many black department heads, including the police and fire commissioners. The reality is that aside from the very tip of the pyramid, local government is dominated by white males.

Overall, city government comes close to matching the city's makeup:

As of this year, the city of Philadelphia is 42 percent black, 36 percent white, 13 percent Latino, and 7 percent Asian. It is 47 percent male.

The city government workforce is 46 percent black, 45 percent white, 5 percent Latino, and 2 percent Asian. It is 59 percent male.

Probe a little deeper and the disparity becomes evident.

For the 4,000-plus city employees who earn $70,000 a year or more, 64 percent are white and 72 percent are male.

For the 4,000 or so city employees who earn $35,000 a year or less, 67 percent are black and 55 percent are male.

The average salary of a white worker ($60,107) is about $10,642 more than the average for a black employee, who earns $49,465.

Two things should be said at this juncture. No one is suggesting that government must match precisely the makeup of the city. And no one is suggesting the disparity in power and pay is due to discrimination.

But, civil service rules - and specifically the Rule of Two - make it difficult to change the mix of employees. A police commissioner, for instance, may want to hire someone who speaks Mandarin for the police force. But, if that applicant isn't among the top two scorers, he is out of the running.

Nor can a department say it will only offer the next 100 openings to Latinos who pass the civil service exam. That would violate civil rights laws.

When it comes to promotions, because the pipeline usually is filled with white males in many departments, the odds favor them taking the next step up.

An example: there are 75 captains in the Philadelphia Police Department. If there was vacancy in the job of police inspector most of them would likely take the civil service exam for that job. Since 87 percent of all police captains are white and 97 percent are male, the odds would favor white males to be among the top two scorers.

Albert D'Attilio, the head of human resources for the city, said that with its Rule of Two, Philadelphia has among the most restrictive hiring rules in the nation. In other cities and states, managers are allowed to pick from a larger pool of applicants. Some have a system that lets them pick from a pool of applicants with the three highest scores. For two positions open, they could have four applicants who get a 92, six who get a 91 and seven who get a 90. This gives the manager a pool of 17 applicants eligible to fill the job.

No one wants to go back to the bad old days when ward leaders had the most input. And there have been attempts to change the City Charter to loosen up the Rule of Two; the latest happened in the early 1990s when Ed Rendell was mayor. But, charter changes must be approved by voters and they voted that proposal down.

Regardless of who is elected, the next mayor should be a proponent of diversity. It doesn't make sense to stick to a formula devised in the 1950s. Times have changed. The city has changed. The city's workforce should reflect that.